Slack cable take-up device



March 14, 1933. J. DUNLOP SLACK CABLE TAKE-UP DEVICE Filed May 31, 1930 ATTONEY Patented Mar. 14, 1933 UNITED STATES APATENT oFF-lcs .TAMS DUNLOP, OF PARK RIDGE, ILLINOIS, ASSIGNOR TO WSTINGHOUSE ELECTRIC AELEV'AIOR COMPANY, A COBlPORATION OF ILLINOIS .n l

SLACK CABLE IlAIKEi-'UP DEVICE v Application filed May 31, 1930.' Serial No. 457,966.

My invention relates to a safety device for elevators, and more specifically to a device for taking-up the slack cable to prevent either the car or the counterweight falling back and snapping the cable when the descent of the other body has been suddenly retarded.

When an elevator car is moving downward at a sufliciently high rate of speed to trip the car safety and the safety is set, the counterweight which has been ascending ydoes not stop as rapidly as does the car and by reason of its inertia will continue to ascend until the cables are slack. The counterweight will then drop back pulling the cables taut and frequently either breaking the cables or pulling them away from the car or the counterweight. This will also occur if the car is stopped suddenly by striking the louder or in any other manner.

If, when traveling in the opposite direction, the counterweight is caught and stopped suddenly, the car, which is ascending at a high rate of speed, will continue traveling upwardly after the counterweight has stopped moving. This will cause a slack condition in the cable supporting the car and, when the car .stops by gravity and starts descending, it will draw the cables taut with such a snap that they are apt to be broken or pulled loose from the car.

Such conditions are especially apt to occur in high speed elevator systems, because of the high rate of speed at which the car or the counterweight is ascending when the other body is stopped.

yIt is, accordingly, an object of my invention to provide means for preventing the occurrence of slack cables with the consequent falling back of either the car or the counterweight, when the motion of the other body has been suddenly retarded.

Itis also an object of my invention to provide a device for taking up any slack cable which may occur to prevent the falling back of either the car or the counterweight.

In accordance with my invention, the cables are attached to the counterweight and/or the car by means of a ratchet device biased by a spring, so that, in the event of the slackening of the cables, the spring will take up vthe slack, keeping the cables taut and preventing the back lash. above referred to.'v l f The invention, both as to its organization and its method of operation, together with additional objectsV and advantages thereof, will best be understood lfrom the following description of a specicembodiment when read vin connection with',V the accompanying drawing, in which:

Figure 1 is a diagrammatic view represent:l ing an elevator system having slack cable take-updevices appliedthere'to in accordance ,with my' invention. -k f Fig. 2 is atop plan view of a slack cable take-up device with the top plate and pulley removed."V 1 y' Fig. 3 is a detail view taken along the section line IIT-III of Fig. 2. j

Fig. 4 is a similar view to Fig. 21but with the top plate and pulley in place. Fig.k 5 is a -view taken on section line V-V ofFigS.v Referring to the drawingI have shown in Fig. 1 a car C supported by cables Ca and counterbalanced by a counterweight C/wt yin the usual manner. f f

In extending-to their point of attachment on either thecar or thecounterweight the cables Ca'pass through an opening 11 in a top plate 12 (shown in Figf) thence around a springtensioned movable pulley 13 and through a partition member -14 where they are anchored in any suitable manner yas shown inFig.3.fvr 'I A By reference toFigs. 2 and 3, it will be seenthat the pulley'13 is'pivotally attached to a movable sling 15. Av rod 16 i's'attached at one end to the slingy and passes slidably through a partition member 17 where the other end of the rod vterminates in a head 18. A compression spring '19, is provided on the rod in concentric relation therewith, andis compressed between the partition member 17 and the 'head 15E-ofthe rod. A

AIt will be apparent that the spring 19 introi the car. But if the tension on the cables is c released for an instant, the spring 19 will v suitable latch or pawl 22 and cooperating rack gear 23 are provided, as shown in Fig. 3.

The stationary idler pulley 21 may be pivotally mounted above the cross-head between a pair of brackets 24 mounted on the top plate 12, as shown in F ig. 5. The idler pulley "21 serves to increase the amount of slack cable that will be taken up by a given movement of the movablev pulley, and prevents the shifting of the suspension point and consequent unbalancing of the car or the counterweight when the device operates.

It will, therefore, be seen that I have provided a device which will take up the slack cable and will prevent'either the car or the counterweight falling back and snapping the cables when the downward motion of the other body has been suddenly retarded.

I do not wish to be restricted to the specific structural details, and arrangement of parts herein set forth, as various modifications thereof may be effected without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. In a slack cable take-up device for elevators, an elevator car, a hoist cable for sup- `May, 1930.

tors, an elevator car, a hoist cable for supporting said car, a movable pulley carried by the elevator car, a spring for biasing the pulley into deilecting engagement with the cable, said spring having insufficient strength to displace the cable while it is normally tensioned by the weight of the car and a stationary idler pulley mounted to engage the hoist cable on the opposite side and above the mov; able pulley. p

In testimony whereof, I have hereunto subscribed my name this twenty-second day of JAMES DUNLOP.

porting the car, a movable pulley carried by the elevator car, a spring for biasing the pulley into detlecting relation with the tensioned l hoist cable, said spring having insuficient strength to displace said cable while it is normally tensioned by the weight of the car, a pawl or latch carried with the movable pulley, stationary rack teeth cooperating with said pawl or latch to prevent movement of the pulley in a direction in opposition to the biasing spring by the tension of the cable, and a stationary idler pulley mounted to engage the hoist cable on the opposite side and above the movable pulley.

2. In a slack cable take-up device for elevators, an elevator car, a hoist cable for supporting the car, a movable pulley carried by the elevator car, a spring for biasing the pulley into deiiecting relation with the tensioned hoist cable, said spring having insuicient strength to displace said cable while it is normally tensioned by the weight of the car, a pawl or latch carried with the movable pulley, stationary rack teeth cooperating with said pawl or latch to prevent movement of the pulley in a direction in opposition to the biasing spring by the tension of the cable.

3. In a slack cable take-up device for eleva- 

